Immobilization of glucose oxidase in polypyrrole/polytetrahydrofuran graft copolymers (original) (raw)
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International Journal of Biological Macromolecules, 2007
In this study, glucose oxidase and polyphenol oxidase were immobilized in conducting polymer matrices; polypyrrole and poly(N-(4-(3-thienyl methylene)-oxycarbonyl phenyl) maleimide-co-pyrrole) via electrochemical method. Fourier transform infrared and scanning electron microscope were employed to characterize the copolymer of (N-(4-(3-thienyl methylene)-oxycarbonyl phenyl) maleimide) with pyrrole. Kinetic parameters, maximum reaction rate and Michealis-Menten constant, were determined. Effects of temperature and pH were examined for immobilized enzymes. Also, storage and operational stabilities of enzyme electrodes were investigated. Glucose and polyphenol oxidase enzyme electrodes were used for determination of the glucose amount in orange juices and human serum and phenolic amount in red wines, respectively.
International Journal of Biological Macromolecules, 2005
Glucose oxidase was immobilized in conducting copolymers of three different types of poly(methyl methacrylate-co-thienyl methacrylate). Immobilization of enzyme was carried out by the entrapment in conducting polymers during electrochemical polymerization of pyrrole on the copolymer electrodes. Maximum reaction rate, Michaelis-Menten constants, temperature, pH and operational stabilities were determined for immobilized enzyme. The amount of glucose in orange juices of Turkey was investigated by using enzyme electrodes.
Reactive and Functional Polymers, 2003
In this study, immobilizations of enzymes, invertase and glucose oxidase, were achieved in conducting copolymers of N-pyrrolyl terminated polydimethylsiloxane/polypyrrole (PDMS/PPy) matrices via electrochemical polymerization. The kinetic parameters, v max (maximum reaction rate) and K m (substrate affinity), of both free and immobilized enzymes were determined. The effect of supporting electrolytes, p-toluene sulfonic acid and sodium dodecyl sulfate, on enzyme activity and film morphologies was examined. The optimum temperatures and operational stabilities of immobilized enzymes were determined. PDMS/PPy copolymer matrix was found to exhibit significantly enhanced properties compare to pristine polypyrrole in terms of relative enzyme activities, kinetic parameters and operational stabilities.
Enzyme Electrodes for Glucose Oxidation Prepared by Electropolymerization of Pyrrole
Process Safety and Environmental Protection, 2007
In this work, a method of fabricating enzyme electrodes with the potential application for biofuel cells and biosensors was investigated. Enzyme electrodes were prepared by entrapping native glucose oxidase (GOx) and ferrocene wired GOx (FeFcGOx), as the dopants, in conducting polypyrrole matrices by electropolymerization. Furthermore, the developed polymer enzyme layer was characterized by physical and electrochemical analysis, and glucose oxidation activity on both electrodes was studied. Both electrodes showed direct electrical communication between the enzyme and electrode surface. Low glucose oxidation current was observed from the electrode containing GOx. Higher glucose oxidation current was obtained with FeFcGOx, and the current increased with the escalating glucose concentration suggesting that efficient electron transfer between the enzyme and the electrode surface were achieved. A maximum sensitivity of 20 mM for glucose concentration was obtained for the polymer electrode prepared from FeFcGOx.
Improved model of a polypyrrole glucose oxidase modified electrode
Journal of Electroanalytical Chemistry, 1995
The behaviour of an electrode modified by entrapment of glucose oxidase in an insulating polypyrrole film is examined using both an experimental study and a theoretical model. Although adsorption of glucose oxidase at the electrode surface and at the polymer ]solution interface was shown experimentally, more than 90% of the amperometric responsc due to the glucose oxidation was generated by the enzyme confined inside the polymeric matrix. The maximum amperomctric response was obtained with a polypyrrole film of thickness 250 nm; the global process rate was governed by the kinetics of the catalysed reaction for thin films and by the mass transport of the species in the polymer for thicker films. All the experimental results were tilted correctly by a complete model using the same values of the physicochemical parameters in all cases. In particular, the theoretical results agreed well with the enzyme location determined experimentally; furthermore, they permitted the prediction that the amperometric response decreased when solution stirring increased. The simulation of the theoretical concentration profiles confirmed that the external mass transport of all species in the solution had to be taken into account and showed that the enzymatic reaction occurred preferentially near the polymer ]solution interface. This last result suggested some improvements in the design of the electrode.
2006
Incorporation of the glucose in presence of phosphate and acetate buffer were studied to investigate the poly(N-methylpyrrole)/polyvinyl sulfonic acid/sodium nitrate/glucose oxidase (P(NMP)/PVS/NaNO 3 /GODx) electrode. The P(NMP)/PVS/NaNO 3 films were electrochemically synthesized and characterized by using electrochemical technique, FTIR and SEM. Glucose oxidase was immobilized by cross-linking via glutaraldehyde on the galvanostatically synthesized poly(N-methylpyrrole) /polyvinyl sulfonic acid/sodium nitrate (P(NMP)/PVS/NaNO 3) film. The higher sensitivity of P(NMP)/PVS/NaNO 3 /GODx electrode was recorded in phosphate buffer than that of acetate buffer and that was found to be 4 µA/mM and 2.2 µA/mM, respectively. The kinetics parameters of P(NMP)/PVS/NaNO 3 /GODx electrode were determined for the phosphate buffer and acetate buffer. In phosphate buffer the observed values of K m and I max were 14.4 mM and 111.2 µA, respectively and in acetate buffer 16.9 mM and 68 µA, respectively. The stability of synthesized P(NMP)/PVS/NaNO 3 /GODx electrode in phosphate buffer was found to be more than that of acetate buffer.
An alternative supporting electrolyte for enzyme immobilization in conducting polymers
International Journal of Biological Macromolecules, 2008
In this study an alternative supporting electrolyte was used in enzyme immobilization. Invertase was studied to observe the effect of the supporting electrolyte. Sulfonated poly(arylene ether sulfone) was used as the supporting electrolyte during the electrolysis of pyrrole. The results show that the polymeric supporting electrolyte can be used instead of sodium dodecyl sulfate.
Journal of Applied Polymer Science, 2006
Two new ultrafiltration membranes were obtained from a polymer mixture, containing 60% polyacrylonitrile (PAN) and 40% copolymer of methylmethacrylatedichlorophenylmaleimide (MMA-DCPMI). Membrane 1 (MB1) contains 40% DCPMI of the copolymer, and membrane 2 (MB2) contains 15% of the copolymer. The pore size, the specific surface, the water content, the water flux, and the selectivity were determined for the two membranes. The presence of dichlorophenylmaleimide in the copolymer ensures the preparation of membranes suitable for direct covalent enzyme immobilization without further modifications. These membranes were used for immobilization of glucose oxidase (GOD). High amount of bound protein was found on each of the membranes. High relative activities of the immobilized GOD were achieved, 72% for MB1 and 68% for MB2. The properties of the immobilized enzyme (GOD) were determined: optimum pH and temperature and pH, thermal, and storage stability, and then compared with the properties of the native enzyme. The kinetic parameters of the enzyme reaction, Michaelis constant (K m) and maximum reaction rate (V max), were also investigated. The results obtained showed that the ultrafiltration membranes prepared from the mixture of PAN and the copolymer MMA-DCPMI were suitable for use as carriers for the immobilization of GOD.
J. Chem. Soc., Faraday Trans., 1992
Glucose oxidase and ferro/ferricyanide can be co-immobilised in poly(N-methylpyrrole) films. The two species compete for incorporation into the films so that on increasing the concentration of enzyme in the growth solution less ferro/ferricyanide is incorporated into the film, and vice versa. The ferro/ferricyanide entrapped within the film acts as a redox mediator for the oxidation of the enzyme at 0.45 V vs. SCE. Studies of the effect of variation of film thickness, glucose concentration, enzyme loading and ferro/ferricyanide loading are consistent with a model in which diffusion and enzyme-catalysed reaction within the film are coupled. Analysis of data from these experiments allows the rate parameters for these processes to be determined. These data are compared with previous results for oxygen mediation in poly(N-methylpyrrole) films.
Immobilization of glucose oxidase onto membranes of modified acrylonitrile copolymer
Journal of Applied Polymer Science, 1994
Acrylonitrile copolymer was modified with sodium hydroxide and l,6-hexamethylen diamine (1) and with hydroxylamine (2). The amount of amine and carboxylic groups was studied as a function of the modification conditions. Membranes were prepared from the modified copolymer by the phase-inversion method. They were used as matrix for covalent immobilization of glucose oxidase by using glutaraldehyde. The amount of bound protein, relative activity, and storage of the activity of the immobilized enzyme were determined. The results were compared with those obtained with glucose oxidase immobilized onto the surfacemodified membrane of acrylonitrile copolymer with sodium hydroxide and 1,6-hexamethylendiamine and with hydroxylamine. The results were proved by scanning electron microscopy.